constraint generate a phone number pattern

constraint generate a phone number pattern:-

 class PhoneNumber;

  rand bit  [2:0]  area_code;

   rand bit [3:0]  number;

  //constraint valid_area_code {

  //  area_code inside {[2:9]};}

constraint valid_area_code {

   area_code <=9;}

 //constraint valid_number{

   //    number inside{[9:0]};}

 constraint valid_number{number<=9;}

 function void print();

    

          endfunction

endclass

PhoneNumber num=new;

module test;

initial

 repeat(10)

begin 

    num.randomize();

   $display("phone number : %d",num.number);

   $display("area code : %d", num.area_code); 

num.print();

end

endmodule